<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    let a = "helloWorld";
    console.log(a);
    console.log(typeof  a);

    // 数字
    let b = 10;
    let c = 3.14;
    console.log(typeof  b);
    console.log(typeof c);

    let d = true;
    console.log(typeof d);

    let e;
    console.log(typeof e);

    let object = new Object();
    console.log(typeof object);

    object.aa = 10;
    object.bb = "js";

    console.log(obj);
    

</script>
</body>
</html>